Hindsight is 20/20. As I look back on nearly 13 years of competitive racing, I want to change a lot of my past training. I made a lot of mistakes - small decisions that resulted in an injury, a poor race or missing half a year of running.

When we launched the handstand challenge last week, I confessed that I’m not really comfortable with being upside down — but I hoped to change that. Yesterday I did a handstand against a wall for the first time, and felt strong and stable. I’ll let you in on a few secrets.

Everybody at the gym has their own plan, their own path. In a perfect world, these paths all crisscross and interweave without any collisions. One person hops off the treadmill, another hops on. One person sets down a weight, another picks it up. Record scratch, here's the real world: five different people across the gym are killing time on machines they don't care about, glaring at the guy who won't stop doing curls in the squat rack.

We all know that working out is important, but sometimes actually making it to the gym is easier said than done. This week ClassPass unveiled a new app that can potentially make squeezing a workout in those days a little easier.

Every box jump involves a leap of faith. You’ll probably land on top of the box, on your feet, and not make it into one of those box jump fail compilation videos (seriously, do not Google). But how do you convince your brain and body that a solid landing awaits?

If you work at a computer, good posture is important, but difficult to remember throughout the day. These three quick exercises help undo some of the effects of slouching at a computer for hours.

I cannot do a handstand. Or a headstand. I get kind of terrified even just trying to put my legs up above me onto a wall. Are you with me? Let’s get out of our comfort zones. If you can already do handstands, well, I’ll have some extra challenges for you too.

Dear Lifehacker, I've heard that I should be "mixing it up" and changing up my workouts at the gym. My friend, who's a bodybuilder, told me that this is called "muscle confusion" and will force them to grow. I only know a few exercises at the gym so changing seems even more difficult. What do I do?

We all hit a slump near the beginning of a fitness program. Not at the very start, when we’re excited to get going — more like a few weeks in. It may take six weeks to notice more muscle or better endurance, but how do you get through that time without losing hope?

Five people have recently told me they were going to "try keto" — the most recent after gushing about a mutual friend who has been doing keto, aka the popular ketogenic diet, and getting awesome-looking results. You've probably heard rumblings about keto, but what the heck is it? And is it too good to be true?

Squatting seems so complicated when somebody is telling you all the things that can go wrong — knees behind toes! Butt farther down! Head up! But not too up! If you’re following our challenge, you’re probably doing a lot more squats than you ever have before, so let’s talk about how we’re doing them.

Finding clear, definitive facts about healthy exercise can be difficult. The exercise industry is a multi-billion dollar business, built partially on selling gadgets and supplements to people desperate to lose weight or look attractive. Meanwhile, good workout plans and simple truths lurk in the background waiting for their time to shine. All of this results in lots of misinformation about exercise. We're taking some of those commonly-held exercise myths to task, and we have science to back us up. Let's get started.

Squats can be as hard or as easy as you want them to be. If you’re doing 100 a day, you may need to ease up to be able to get your quota in without making yourself too sore. And if you’re a total beginner, you may find the simplest squats to be more than enough of a challenge. Here are a few to try.

You spend two minutes in the morning and two at night brushing your teeth. Instead of just standing around, make even better use of that time by incorporating a few simple movements for balance, flexibility and strength.

Killer workouts come with bragging rights: can you believe you survived that? But you can get a perfectly good sweat on without doing anything labelled "high intensity" or headed by a sadistic coach. It's okay for a workout not to feel like torture, but only like work.

Fat loss relies on one thing: eating fewer calories than you expend. But nobody wants to sit and count calories all day. Most people can learn to track them successfully, but some might need a different strategy altogether. If tracking has given you a headache in the past, consider giving this a try.

We're bringing the June fitness challenge home to a glorious conclusion today. Have you done burpees every single day? (Just some days? Hey, better than nothing.) I'm using some of my newfound strength for a grand finale — you should too.

Get ready for strong legs and a poppin' butt, because July's fitness challenge is squats! This is the classic lower body exercise for a reason: Squats build pretty much every muscle below the waist, and there are a ton of variations for all fitness levels.

Every overnight success is years in the making. Boxing trainer Leyon Azubuike's first attempt at starting a gym didn't pan out, but he went back to work as a private coach and tried again. Now his gym, Gloveworx, has two LA locations and is soon expanding to New York. We talked to him about his career path, his coffee substitute, and how he still runs private training sessions while managing a growing business.